PROCEDURE PWITHR(INTEGER ARRAY A; INTEGER N; REFERENCE BOOLEAN LAST);
comment  collected algorithms #306;
   begin
   integer i,p,q,r;
   label l12,l9,l4,l5,l2,l1,l3,l11,l6,l7,l8,l10,l99;
   own integer m; own integer array b[1:100];
   if ¬last then goto l12; last←false;
   for i←1 step 1 until n do b[i]←a[i];
   p←b[n];
   for i←n step -1 until 1 do
      if p≠b[i] then
         begin m←i; go to l99 end;
   m←0; go to l99;
l12: if m=0 then goto l10;
   p←b[m]; q←m; r←0;
l9:  i←n;
l4:  if a[i]=p then goto l2;
   if a[i]<p then r←i;
l5: i←i-1; goto l4;
l2: a[i]←b[n]-1; if r=0 then goto l8;
l1: a[r]←p; q←q+1;
l3: r←r+1; if r>n then goto l11 else if a[r]>p then goto l3;
l11: if b[q]=p then goto l1; r←0;
l6: r←r+1; if a[r]≥p then goto l6;
   a[r]←b[q]; if q=n then goto l7;
   q←q+1; goto l6;
l7: last←false; goto l99;
l8: q←q-1; if q=0 then goto l10;
   if b[q]=p then goto l5;
   p←b[q]; goto l9;
l10: last←true;
l99:
   end;